Industry supports WRAP projects on green pavement technology
Specification trials are now underway to test a new kind of green pavement technology, used to create foundation layers of modern road surfaces.
The trials, which are integral to two projects, being funded by WRAP (the Waste & Resources Action Programme), are being led by Tarmac, Scott Wilson and the Transport Research Laboratory (TRL). They are taking place at Tarmac's Colchester Quarry and involve using recycled and secondary aggregates(RSA) in hydraulically bound mixtures (HBMs) produced using slow cementing binders derived from various industrial by-products.
Dr Howard Robinson, Tarmac's head of product development, comments:
'HBM technology has been around in the UK for sometime. However, difficulty maintaining supplies of some materials, combined with a lack of certainty about the performance and durability of the mixtures, have been a barrier to specification.
'Over the past decade we have been experimenting to produce HBMs made using various alternative materials such as granulated blastfurnace slag and pulverised fuel ash (PFA) and we believe these are much more viable industry alternatives.
'In particular, these HBM materials are more readily available and can be produced using the same mobile mixer plant used for foamed bitumen-based mixes, such as Tarmac FoamMaster."
Dr Nizar Ghazireh, technical director at Scott Wilson, says:
'In total, four different HBMs are being tested as part of the trials. The tests will produce in-situ performance data to relate the performance of these materials to the new specifications and design guidance.
Dr Howard Robinson comments:
'This new performance data will enable local authorities, the Highways Agency and other customers to specify HBM foundation layers with confidence and we are predicting this will lead to an increase in demand.
'In the future we believe a significant proportion of sub-bases and bases used will consist of HBMs produced from recycled materials."
Having invested extensively in its road recycling capabilities since the start of the year, Tarmac is committed to the take-up of this new green pavement technology should the trials prove successful. In particular,Tarmac has recently acquired new hi-tech processing plant, which can be used to mix HBM and other recycled mixes as close to the site as possible.
John Barritt, aggregates technical adviser at WRAP, concludes:
'HBM is an exciting area of opportunity for the road surfacing industry, which will add value to secondary and recycled aggregates by extending their suitability for a wider range of applications. The trials are taking place in July and will be monitored for one year thereafter with the results published by WRAP during 2007."
ENDS
Part of Anglo American plc, one of the world's largest mining and natural resource companies, Tarmac Group is the market leader in the UK in aggregates, mortar, concrete blocks and asphalt and number two in ready-mixed concrete. Through it's enhanced network of regional production units and plants it provides a vast range of products for the construction industry nationwide.
WRAP (the Waste & Resources Action Programme) is a major UK programme established to promote resource efficiency. Its particular focus is on creating stable and efficient markets for recycled materials and products and removing the barriers to waste minimisation, re-use and recycling. A not-for-profit company, WRAP is backed by substantial Government funding from Defra and the devolved administrations in Scotland, Wales and Northern Ireland. Details of all WRAP's activities are available at www.wrap.org.uk
For further information please contact Christine Smart, Rebecca Cowley, Delia Elcock or Andrew Hutson at IAS SMARTS on 0121 456 3199.
